What is the main purpose of this code?

To provide a standard procedure for the application of cork insulation on pipes, ducts, and vessels to ensure effective and durable thermal performance. (Scope 1.1)

Is a vapour barrier required for cork on cold lines?

Yes, a suitable vapour barrier finish is essential for all cold applications to prevent moisture ingress, which degrades insulation performance. (Clause 4.1.2)

How should multiple layers of cork insulation be installed?

All joints in succeeding layers should be staggered with respect to the joints in the preceding layer to avoid thermal bridges. (Clause 3.3.4)

What material is recommended for the vapour barrier?

The code suggests two coats of bituminous mastic compound applied over the insulation surface. (Clause 4.1.2)

IS 6537

: 1981

Code of practice for insulating cork slabs and pipe sections

CurrentSpecializedCode of PracticeMEP · Insulation Materials

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This code of practice outlines the methods for applying baked granulated cork slabs and pipe sections for thermal insulation purposes. It details the requirements for surface preparation, adhesive application, installation procedures, and protective finishes for both hot (up to 90°C) and cold surfaces. The standard also provides guidance on selecting appropriate insulation thickness to prevent condensation and control heat transfer.

Provides guidance on the use of insulating cork slabs and pipe sections.

Quick Reference Values

Recommended maximum service temperature90 °C

Recommended minimum service temperature-180 °C

Nominal density range for material110 to 140 kg/m³

Maximum thermal conductivity at 10°C mean temp0.038 W/(m.K)

Minimum number of binding wires per section2 per 900 mm length

Practical Notes

This standard is for natural cork insulation, which is less common today than synthetic materials like nitrile rubber or rockwool, but is still valued for its sustainable properties and specific applications (e.g., wineries).

Proper surface preparation (clean, dry, and free of rust/grease) as per Clause 3.1 is critical for the long-term performance of the insulation system.

The selection and application of a suitable vapour barrier (Clause 4.1.2) is the most important step for cold insulation to prevent moisture ingress and failure.